Auto merge of #68831 - Dylan-DPC:rollup-j6x15y9, r=Dylan-DPC

Rollup of 7 pull requests

Successful merges:

 - #68282 (Instrument C / C++ in MemorySanitizer example)
 - #68758 (Fix 59191 - ICE when macro replaces crate root with non-module item)
 - #68805 (bootstrap: fix clippy warnings)
 - #68810 (Remove Copy impl from OnceWith)
 - #68815 (remove redundant imports (clippy::single_component_path_imports))
 - #68818 (fix couple of perf related clippy warnings)
 - #68819 (Suggest `split_at_mut` on multiple mutable index access)

Failed merges:

r? @ghost

src/bootstrap/bin/rustc.rs

@@ -47,7 +47,7 @@ fn main() {
     };
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
-    let on_fail = env::var_os("RUSTC_ON_FAIL").map(|of| Command::new(of));
+    let on_fail = env::var_os("RUSTC_ON_FAIL").map(Command::new);
 
     let rustc = env::var_os(rustc).unwrap_or_else(|| panic!("{:?} was not set", rustc));
     let libdir = env::var_os(libdir).unwrap_or_else(|| panic!("{:?} was not set", libdir));
@@ -64,7 +64,7 @@ fn main() {
     if let Some(crate_name) = crate_name {
         if let Some(target) = env::var_os("RUSTC_TIME") {
             if target == "all"
-                || target.into_string().unwrap().split(",").any(|c| c.trim() == crate_name)
+                || target.into_string().unwrap().split(',').any(|c| c.trim() == crate_name)
             {
                 cmd.arg("-Ztime");
             }
@@ -189,7 +189,7 @@ fn main() {
                 crate_name,
                 is_test,
                 dur.as_secs(),
-                dur.subsec_nanos() / 1_000_000
+                dur.subsec_millis()
             );
 
             match status.code() {

src/bootstrap/bin/rustdoc.rs

@@ -61,7 +61,7 @@ fn main() {
     }
 
     // Needed to be able to run all rustdoc tests.
-    if let Some(_) = env::var_os("RUSTDOC_GENERATE_REDIRECT_PAGES") {
+    if env::var_os("RUSTDOC_GENERATE_REDIRECT_PAGES").is_some() {
         // This "unstable-options" can be removed when `--generate-redirect-pages` is stabilized
         if !has_unstable {
             cmd.arg("-Z").arg("unstable-options");

src/bootstrap/builder.rs

@@ -510,17 +510,15 @@ impl<'a> Builder<'a> {
             Subcommand::Format { .. } | Subcommand::Clean { .. } => panic!(),
         };
 
-        let builder = Builder {
+        Builder {
             build,
             top_stage: build.config.stage.unwrap_or(2),
             kind,
             cache: Cache::new(),
             stack: RefCell::new(Vec::new()),
             time_spent_on_dependencies: Cell::new(Duration::new(0, 0)),
             paths: paths.to_owned(),
-        };
-
-        builder
+        }
     }
 
     pub fn execute_cli(&self) {
@@ -753,13 +751,12 @@ impl<'a> Builder<'a> {
             cargo.env("RUST_CHECK", "1");
         }
 
-        let stage;
-        if compiler.stage == 0 && self.local_rebuild {
+        let stage = if compiler.stage == 0 && self.local_rebuild {
             // Assume the local-rebuild rustc already has stage1 features.
-            stage = 1;
+            1
         } else {
-            stage = compiler.stage;
-        }
+            compiler.stage
+        };
 
         let mut rustflags = Rustflags::new(&target);
         if stage != 0 {
@@ -1252,12 +1249,7 @@ impl<'a> Builder<'a> {
         };
 
         if self.config.print_step_timings && dur > Duration::from_millis(100) {
-            println!(
-                "[TIMING] {:?} -- {}.{:03}",
-                step,
-                dur.as_secs(),
-                dur.subsec_nanos() / 1_000_000
-            );
+            println!("[TIMING] {:?} -- {}.{:03}", step, dur.as_secs(), dur.subsec_millis());
         }
 
         {
@@ -1302,7 +1294,7 @@ impl Rustflags {
 
     fn arg(&mut self, arg: &str) -> &mut Self {
         assert_eq!(arg.split_whitespace().count(), 1);
-        if self.0.len() > 0 {
+        if !self.0.is_empty() {
             self.0.push_str(" ");
         }
         self.0.push_str(arg);

src/bootstrap/builder/tests.rs

@@ -19,7 +19,6 @@ fn configure(host: &[&str], target: &[&str]) -> Config {
     config.out = dir;
     config.build = INTERNER.intern_str("A");
     config.hosts = vec![config.build]
-        .clone()
         .into_iter()
         .chain(host.iter().map(|s| INTERNER.intern_str(s)))
         .collect::<Vec<_>>();

src/bootstrap/compile.rs

@@ -18,7 +18,6 @@ use std::str;
 use build_helper::{output, t, up_to_date};
 use filetime::FileTime;
 use serde::Deserialize;
-use serde_json;
 
 use crate::builder::Cargo;
 use crate::dist;
@@ -149,7 +148,8 @@ fn copy_third_party_objects(
     // which is provided by std for this target.
     if target == "x86_64-fortanix-unknown-sgx" {
         let src_path_env = "X86_FORTANIX_SGX_LIBS";
-        let src = env::var(src_path_env).expect(&format!("{} not found in env", src_path_env));
+        let src =
+            env::var(src_path_env).unwrap_or_else(|_| panic!("{} not found in env", src_path_env));
         copy_and_stamp(Path::new(&src), "libunwind.a");
     }
 
@@ -361,7 +361,7 @@ impl Step for StartupObjects {
                 );
             }
 
-            let target = sysroot_dir.join(file.to_string() + ".o");
+            let target = sysroot_dir.join((*file).to_string() + ".o");
             builder.copy(dst_file, &target);
             target_deps.push(target);
         }
@@ -515,7 +515,7 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: Interne
         .env("CFG_VERSION", builder.rust_version())
         .env("CFG_PREFIX", builder.config.prefix.clone().unwrap_or_default());
 
-    let libdir_relative = builder.config.libdir_relative().unwrap_or(Path::new("lib"));
+    let libdir_relative = builder.config.libdir_relative().unwrap_or_else(|| Path::new("lib"));
     cargo.env("CFG_LIBDIR_RELATIVE", libdir_relative);
 
     if let Some(ref ver_date) = builder.rust_info.commit_date() {
@@ -843,11 +843,11 @@ pub fn run_cargo(
         };
         for filename in filenames {
             // Skip files like executables
-            if !filename.ends_with(".rlib")
-                && !filename.ends_with(".lib")
-                && !filename.ends_with(".a")
-                && !is_dylib(&filename)
-                && !(is_check && filename.ends_with(".rmeta"))
+            if !(filename.ends_with(".rlib")
+                || filename.ends_with(".lib")
+                || filename.ends_with(".a")
+                || is_dylib(&filename)
+                || (is_check && filename.ends_with(".rmeta")))
             {
                 continue;
             }
@@ -905,7 +905,7 @@ pub fn run_cargo(
     for (prefix, extension, expected_len) in toplevel {
         let candidates = contents.iter().filter(|&&(_, ref filename, ref meta)| {
             filename.starts_with(&prefix[..])
-                && filename[prefix.len()..].starts_with("-")
+                && filename[prefix.len()..].starts_with('-')
                 && filename.ends_with(&extension[..])
                 && meta.len() == expected_len
         });

src/bootstrap/config.rs

@@ -16,7 +16,6 @@ use crate::flags::Flags;
 pub use crate::flags::Subcommand;
 use build_helper::t;
 use serde::Deserialize;
-use toml;
 
 /// Global configuration for the entire build and/or bootstrap.
 ///
@@ -440,7 +439,7 @@ impl Config {
                     }
                 }
             })
-            .unwrap_or_else(|| TomlConfig::default());
+            .unwrap_or_else(TomlConfig::default);
 
         let build = toml.build.clone().unwrap_or_default();
         // set by bootstrap.py
@@ -539,7 +538,7 @@ impl Config {
             config.llvm_ldflags = llvm.ldflags.clone();
             set(&mut config.llvm_use_libcxx, llvm.use_libcxx);
             config.llvm_use_linker = llvm.use_linker.clone();
-            config.llvm_allow_old_toolchain = llvm.allow_old_toolchain.clone();
+            config.llvm_allow_old_toolchain = llvm.allow_old_toolchain;
         }
 
         if let Some(ref rust) = toml.rust {
@@ -606,7 +605,7 @@ impl Config {
                 target.ar = cfg.ar.clone().map(PathBuf::from);
                 target.ranlib = cfg.ranlib.clone().map(PathBuf::from);
                 target.linker = cfg.linker.clone().map(PathBuf::from);
-                target.crt_static = cfg.crt_static.clone();
+                target.crt_static = cfg.crt_static;
                 target.musl_root = cfg.musl_root.clone().map(PathBuf::from);
                 target.wasi_root = cfg.wasi_root.clone().map(PathBuf::from);
                 target.qemu_rootfs = cfg.qemu_rootfs.clone().map(PathBuf::from);

src/bootstrap/dist.rs

@@ -828,7 +828,7 @@ impl Step for Analysis {
         assert!(builder.config.extended);
         let name = pkgname(builder, "rust-analysis");
 
-        if &compiler.host != builder.config.build {
+        if compiler.host != builder.config.build {
             return distdir(builder).join(format!("{}-{}.tar.gz", name, target));
         }
 
@@ -877,7 +877,7 @@ fn copy_src_dirs(builder: &Builder<'_>, src_dirs: &[&str], exclude_dirs: &[&str]
             Some(path) => path,
             None => return false,
         };
-        if spath.ends_with("~") || spath.ends_with(".pyc") {
+        if spath.ends_with('~') || spath.ends_with(".pyc") {
             return false;
         }
 

src/bootstrap/doc.rs

@@ -560,7 +560,7 @@ impl Step for Rustdoc {
         builder.ensure(Rustc { stage, target });
 
         // Build rustdoc.
-        builder.ensure(tool::Rustdoc { compiler: compiler });
+        builder.ensure(tool::Rustdoc { compiler });
 
         // Symlink compiler docs to the output directory of rustdoc documentation.
         let out_dir = builder.stage_out(compiler, Mode::ToolRustc).join(target).join("doc");

src/bootstrap/flags.rs

@@ -571,7 +571,7 @@ fn split(s: &[String]) -> Vec<String> {
 }
 
 fn parse_deny_warnings(matches: &getopts::Matches) -> Option<bool> {
-    match matches.opt_str("warnings").as_ref().map(|v| v.as_str()) {
+    match matches.opt_str("warnings").as_deref() {
         Some("deny") => Some(true),
         Some("warn") => Some(false),
         Some(value) => {

src/bootstrap/install.rs

@@ -126,9 +126,8 @@ fn add_destdir(path: &Path, destdir: &Option<PathBuf>) -> PathBuf {
         None => return path.to_path_buf(),
     };
     for part in path.components() {
-        match part {
-            Component::Normal(s) => ret.push(s),
-            _ => {}
+        if let Component::Normal(s) = part {
+            ret.push(s)
         }
     }
     ret

src/bootstrap/lib.rs

@@ -444,7 +444,7 @@ impl Build {
             builder.execute_cli();
         } else {
             let builder = builder::Builder::new(&self);
-            let _ = builder.execute_cli();
+            builder.execute_cli();
         }
 
         // Check for postponed failures from `test --no-fail-fast`.
@@ -839,7 +839,7 @@ impl Build {
             .target_config
             .get(&target)
             .and_then(|t| t.musl_root.as_ref())
-            .or(self.config.musl_root.as_ref())
+            .or_else(|| self.config.musl_root.as_ref())
             .map(|p| &**p)
     }
 

src/bootstrap/metadata.rs

@@ -5,7 +5,6 @@ use std::process::Command;
 
 use build_helper::output;
 use serde::Deserialize;
-use serde_json;
 
 use crate::cache::INTERNER;
 use crate::{Build, Crate};

src/bootstrap/native.rs

@@ -15,8 +15,6 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 
 use build_helper::{output, t};
-use cc;
-use cmake;
 
 use crate::builder::{Builder, RunConfig, ShouldRun, Step};
 use crate::cache::Interned;
@@ -205,7 +203,7 @@ impl Step for Llvm {
             cfg.define("LLVM_ENABLE_LIBXML2", "OFF");
         }
 
-        if enabled_llvm_projects.len() > 0 {
+        if !enabled_llvm_projects.is_empty() {
             enabled_llvm_projects.sort();
             enabled_llvm_projects.dedup();
             cfg.define("LLVM_ENABLE_PROJECTS", enabled_llvm_projects.join(";"));

src/bootstrap/test.rs

@@ -1424,13 +1424,10 @@ impl Step for ErrorIndex {
 }
 
 fn markdown_test(builder: &Builder<'_>, compiler: Compiler, markdown: &Path) -> bool {
-    match fs::read_to_string(markdown) {
-        Ok(contents) => {
-            if !contents.contains("```") {
-                return true;
-            }
+    if let Ok(contents) = fs::read_to_string(markdown) {
+        if !contents.contains("```") {
+            return true;
         }
-        Err(_) => {}
     }
 
     builder.info(&format!("doc tests for: {}", markdown.display()));

src/bootstrap/tool.rs

@@ -234,7 +234,7 @@ pub fn prepare_tool_cargo(
         cargo.env("RUSTC_EXTERNAL_TOOL", "1");
     }
 
-    let mut features = extra_features.iter().cloned().collect::<Vec<_>>();
+    let mut features = extra_features.to_vec();
     if builder.build.config.cargo_native_static {
         if path.ends_with("cargo")
             || path.ends_with("rls")

src/bootstrap/toolstate.rs

@@ -124,7 +124,7 @@ fn check_changed_files(toolstates: &HashMap<Box<str>, ToolState>) {
     let output = t!(String::from_utf8(output.stdout));
 
     for (tool, submodule) in STABLE_TOOLS.iter().chain(NIGHTLY_TOOLS.iter()) {
-        let changed = output.lines().any(|l| l.starts_with("M") && l.ends_with(submodule));
+        let changed = output.lines().any(|l| l.starts_with('M') && l.ends_with(submodule));
         eprintln!("Verifying status of {}...", tool);
         if !changed {
             continue;

src/bootstrap/util.rs

@@ -98,7 +98,7 @@ impl Drop for TimeIt {
     fn drop(&mut self) {
         let time = self.1.elapsed();
         if !self.0 {
-            println!("\tfinished in {}.{:03}", time.as_secs(), time.subsec_nanos() / 1_000_000);
+            println!("\tfinished in {}.{:03}", time.as_secs(), time.subsec_millis());
         }
     }
 }

src/doc/unstable-book/src/compiler-flags/sanitizer.md

@@ -170,7 +170,7 @@ Shadow byte legend (one shadow byte represents 8 application bytes):
 ## MemorySanitizer
 
 Use of uninitialized memory. Note that we are using `-Zbuild-std` to instrument
-standard library, and passing `-msan-track-origins=2` to the LLVM to track
+the standard library, and passing `-Zsanitizer-track-origins` to track the
 origins of uninitialized memory:
 
 ```shell
@@ -185,7 +185,15 @@ fn main() {
     }
 }
 
-$ env RUSTFLAGS="-Zsanitizer=memory -Cllvm-args=-msan-track-origins=2" cargo -Zbuild-std run --target x86_64-unknown-linux-gnu
+$ export \
+  CC=clang \
+  CXX=clang++ \
+  CFLAGS='-fsanitize=memory -fsanitize-memory-track-origins' \
+  CXXFLAGS='-fsanitize=memory -fsanitize-memory-track-origins' \
+  RUSTFLAGS='-Zsanitizer=memory -Zsanitizer-memory-track-origins' \
+  RUSTDOCFLAGS='-Zsanitizer=memory -Zsanitizer-memory-track-origins'
+$ cargo clean
+$ cargo -Zbuild-std run --target x86_64-unknown-linux-gnu
 ==9416==WARNING: MemorySanitizer: use-of-uninitialized-value
     #0 0x560c04f7488a in core::fmt::num::imp::fmt_u64::haa293b0b098501ca $RUST/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/src/rust/src/libcore/fmt/num.rs:202:16
 ...

src/libcore/iter/sources.rs

@@ -398,7 +398,7 @@ pub fn once<T>(value: T) -> Once<T> {
 /// See its documentation for more.
 ///
 /// [`once_with`]: fn.once_with.html
-#[derive(Copy, Clone, Debug)]
+#[derive(Clone, Debug)]
 #[stable(feature = "iter_once_with", since = "1.43.0")]
 pub struct OnceWith<F> {
     gen: Option<F>,

src/librustc/traits/mod.rs

@@ -31,7 +31,6 @@ use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use crate::ty::subst::{InternalSubsts, SubstsRef};
 use crate::ty::{self, AdtKind, GenericParamDefKind, List, ToPredicate, Ty, TyCtxt, WithConstness};
 use crate::util::common::ErrorReported;
-use chalk_engine;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;

src/librustc/traits/structural_impls.rs

@@ -2,7 +2,6 @@ use crate::traits;
 use crate::traits::project::Normalized;
 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use crate::ty::{self, Lift, Ty, TyCtxt};
-use chalk_engine;
 use rustc_span::symbol::Symbol;
 use smallvec::SmallVec;